Synthesis and Structure of the First η³‐1,2‐Diphosphaallyl Complexes [(η⁵‐C₅H₅)(CO)₂M{η³‐RPPC(SiMe₃)₂}] (M = Mo, R = tBu, Cy; M = W, R = tBu) from [(η⁵‐C₅H₅)(CO)₂M=P=C(SiMe₃)₂] (M = Mo, W) and Inversely Polarized Phosphaalkenes RP=C(NMe₂)₂ (R = tBu, Cy)

Abstract

Reaction of [(η5‐C5H5)(CO)2M=P=C(SiMe3)2] [where M = Mo (2), W (5)] with the phosphaalkene tBuP=C(NMe2)2 (1a) afforded the η3‐1,2‐diphosphaallyl complexes [(η5‐C5H5)(CO)2M{η3‐tBuPPC(SiMe3)2}], [where M = Mo (3a); M = W (6)]. Similarly, 2 and CyP=C(NMe2)2 (1b; where Cy = cyclohexyl) gave rise to the formation of [(η5‐C5H5)(CO)2Mo{CyPPC(SiMe3)2}] (3b) by a phosphinidene transfer process. Small amounts of [{η5‐C5H5)(CO)2Mo}2{η2:η2‐Cy3P5}] (4) were formed as a minor product. However, treatment of 2 and 5 with HP=C(NMe2)2 (1c) yielded the complexes [(η5‐C5H5)(CO)2M{η2‐(Me3Si)2CH–P=P–C(NMe2)2}] [where M = Mo (9), W (10)]. The novel compounds 3a, 3b, 9 and 10 were characterized by means of spectroscopy (IR, 1H, 13C{1H}, 31P{1H} NMR, MS). Moreover, the molecular structures of 3a, 3b, 4, 6 and 10 were determined by X‐ray diffraction analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)